Hi Renu,
Well, i would suggest that first of all you give an advertisement for the loss of the power of attorney addressing the general public that if anybody is in possession of such power of attorney or claiming in possession to contact you.
Further, hope that power of attorney would be a registered one, since it is for the house with you purchased. If it is so, then the next thing would like to advise it that you need to get a certified copy from the revenue authority, where such power of attorney was earlier registered, by making an application to them.
Thus, if at all you want to sell the house you can always execute a declaration on oath to the intending purchaser that such power of attorney was lost and a due and diligent search was also made by issuing a public notice and it is not found and it is neither mortgaged.....
Thus, if such a power of attorney is lost, i dont think that you shculd execute another... also the person from whom you took is also not available....
Anyways you can get the certified copy of the lost power of attorney... which will sufice the issue...
I have tried to solved your problem, still you may always consult your local lawyer....
Thanks and Regards......